The present invention relates generally to methods and apparatus for reeling a web.
In particular, the invention relates to a method for reeling a web wherein the web is reeled on a core tube which is supported by first and second carrying rolls with the web roll being pressed during formation by a topside pressing roll. The completed web roll is removed utilizing lowering means and substantially simultaneously with the lowering movement, a new core tube is introduced into the throat between the first and second carrying rolls. At this time, the web is cut, preferably without stopping its movement, and the newly cut end of the web is affixed to the new core tube.
Further, the invention relates to apparatus for reeling a web on a core tube comprising first and second carrying rolls and a pressing roll that presses down on the web roll as it is being formed on the core tube. The first and second carrying rolls define first and second nips with the web roll being formed. At least one of the carrying rolls is a driven roll adapted to rotate the core tube and web roll being formed therearound. A device is provided for cutting the web, preferably without stopping its movement, and affixing the newly cut end of the web to the core tube.
Upon completion of a web roll in web reeling operations, it becomes necessary to affix a new or newly cut end of a web to a new core tube. In such situations, it is generally necessary to stop the so-called tambour roll and, after changing the core tube or tubes, begin the rotation of the tambour roll again. Since tambour rolls are quite large and heavy, the braking of the rotation of the tambour roll, especially at the high reeling speeds presently being used which approach about 2000 m/min, causes undesirable wear on various structural components of the reeling apparatus and, additionally, a significant amount of time is required to bring the tambour roll to rest and then up to speed again. Presently, the time required for changing the core tubes is about 30 seconds in mechanized arrangements and about two minutes in the case where the core tubes are manually inserted. Moreover, restarting the large and heavy tambour rolls requires the consumption of relatively large amounts of electric energy.
An arrangement for reeling paper web or the like onto a reel core tube is disclosed in Finnish patent No. 63918. In particular, a reeler includes carrying rolls and a pressing roll for holding the web roll being formed against the carrying rolls. A device is disclosed in the Finnish patent for introducing a new reel core tube during the final stage of reeling of a web roll between that web roll and the carrying rolls. Also disclosed are web cutting means and a device for moving the completed web roll from between the carrying rolls and pressing roll. A device for guiding the cut end of the web so that it encircles the new core tube comprises guide means disposed on different sides of the reel core tube arranged to direct compressed air jets onto the web to guide the web around the core tube all the regions of the nips that interact with the core tube.
In Finnish patent No. 49276, a method is disclosed for reeling a web wherein the web is reeled onto a core tube which is supported by first and second carrying rolls with a topside pressing roll pressing down on the web roll being formed. After completion, the web roll is removed from the carrying rolls by lowering means and substantially simultaneously with the lowering movement, a new core tube is inserted into the throat between the first and second carrying rolls. The web is cut without stopping its movement and the newly cut end of the web is affixed to the core tube. Reeling of the web to form a new web roll begins at a position below the throat defined by the carrying rolls, the newly forming web roll being supported by an underside pressing roll, whereupon the new web is transferred, under the action of the underside pressing roll, through the throat between the carrying rolls which opens to permit such passage.
The main drawback of conventionl arrangements of the type described above is the inability to control the quality of the reeling operation to the extent desired. Problems have also been encountered in the lowering of the completed web roll. For example, the completed web roll is often damaged as it is being lowered.